Time corridor

A time corridor, also called a time-space induction channel and sometimes referred to as a time tunnel, was a form of time travel in which a wormhole was created through the Time Vortex, linking two points together. It was generally considered less advanced than other time travel technologies such as TARDISes. (TV: Timelash) Considered child's play by the Seventh Doctor, one of the basics of time corridor technology was anchoring the exit point, since time corridors were temporary and collapsed when their power was cut. (PROSE: Set Piece)

In order to complete a corridor, the Daleks built time conduits that would serve as the ends of the corridor. If the conduit on a planet was destroyed, the Daleks would no longer be able to reach it via the time corridor. (AUDIO: The Mutant Phase)
The Daleks used a time corridor as a link between themselves and Earth in 1984. There they had deposited samples of the Movellan virus that they would later need. Turlough accidentally travelled through the corridor and so the Doctor followed him in his TARDIS. Both the Daleks and Lytton's men used the corridor numerous times. (TV: Resurrection of the Daleks)

The Sontarans were also developing time corridor technology, constantly improving their advancements whereas the Daleks, at least according to the Sontarans, assumed they achieved perfection and so did not improve their methods. (AUDIO: The Five Companions)

In emergencies, some crafts travelling within a time corridor could deploy an escape time corridor which could latch onto familiar technology. (AUDIO: The Time of the Daleks)

The Eleventh Doctor accidentally jettisoned a room once, inadvertently creating a time corridor and allowing shadowy creatures to pass through and arrive in 1964. They were drawn to Earth because Ethan dropped his mobile phone in 1964, despite coming from 2014, which made them hungry. (COMIC: The Door to a Winter Long Ago)

According to the invalid source, Doctor Who: The Dalek Handbook, after the end of the civil war and the defeat of the Humanised Daleks, the Emperor Dalek decided that the Daleks, in order to succeed in their conquests, would have to change history, thus time travel was put into greater use by the race.